The proposed research seeks to illuminate the mechanisms of human memory and, in particular, how we search memory to recall specific details from an event. Behavioral studies demonstrate that subjects use two types of associations to cue memory during recall: those based on temporal contiguity of items and those based on pre-existing semantic relations. The first aim seeks to dissociate the neural correlates of these two types of memory cues by means of a cued- and free- recall study with both functional magnetic-resonance imaging (fMRI) and scalp electroencephalographic (EEG) recordings. Univariate statistical methods will indicate the brain areas and type of neural activity associated with the trade-off between semantic and episodic memory cues. In addition, multivariate pattern classification of the fMRI and scalp EEG data will provide a neural readout of a subject's cue state at any given time. The second aim makes use of this neural readout to constrain a computational model of the interaction between semantic and temporal cues during memory retrieval. Relevance: In many cases, memory problems arise not just due to the inability to encode new information, but the inability to access information that we have stored in our brains. An improved understanding of memory retrieval can be expected to have important health consequences for both the enhancement of memory performance in general and the treatment of memory impairments due to head traumas or disease.